Deneb -- the brightest star of Cygnus, the swan -- stands high in the eastern sky at nightfall at this time of year. It forms the northernmost point of the big Summer Triangle, so it's pretty easy to pick out.

Deneb's brilliance makes it a popular target for casual skywatchers, but not necessarily for the pros.

They already know the basics about Deneb: It's a blue supergiant that's perhaps 1500 light-years away, and it's going through some changes that may cause it to get even bigger, and to change colors from blue to orange. But a lot of questions remain.

It's hard to get answers because there just isn't a lot of time available to study an individual star.

Most of the observing time on the world's biggest telescopes is devoted to relatively faint objects -- things like distant galaxies and quasars.

And when they do look at a bright star, it's usually as part of a study of a group of similar objects -- blue supergiants, for example, or stars that pulse in the same way that Deneb does.

To study a star in detail, astronomers tend to use smaller telescopes. A study about Deneb released earlier this year, for example, used more than 300 nights of observations made with a one-meter telescope, which is pretty small by modern standards.

Studies like these have answered some of the questions about Deneb. But as is almost always the case in science, they've raised a lot more -- questions that may take some time to answer.

Script by Damond Benningfield, Copyright 2011

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